The regular water supply through the overhead tanks has sufficient pressure for these water purifiers to function. However, it is not so with Reverse Osmosis (RO) water purifying technology.
The RO water purification process requires forcing the source water through a semipermeable membrane to separate TDS, unwanted large molecules, and toxic contaminants. However, the pressure exerted by normal tap water is insufficient to push the water through the membrane. Hence, all RO water purifiers have a booster pump to force the water through the RO membrane. Generally, these pumps are inbuilt into the RO water purifying machines. These pumps usually work at 50 psi.
However, users can install a separate booster pump if the normal water pressure is insufficient (lower than 40 psi). This additional power is necessary to force the water through the RO membrane.
What will happen if you do not use a booster pump?
The absence of a booster pump will result in less water being forced through the membrane, resulting in more wastewater. So, a water booster pump is essential if the water pressure is less than 40 psi.
A Booster Pump variant
The Kent Zero Water Wastage RO water purifier requires an additional booster motor to pump the 6 Ways you can use Waste Water from RO water purifier! to overhead tanks. This system differs from traditional RO systems because it recirculates the rejected water from the machine to overhead tanks.